RE the derailleurs and other small parts - the best method when they are that dirty is to soak them in solvent in a coffee can or whatever, then clean with a soft brush. You can use Simple Green (etc) if you prefer.

Alternatively, you can spray them with WD40, and then brush them and clean them with a rag. This method may take 2-3 applications to get things clean.

After cleaning the dirt and grease, polish as desired. I use Simichrome polish on both aluminum and chrome, but any paste metal polish will work.

When that's done, relube all pivot points with oil or grease. Like elcraft says, the Jubilee rear derailleur has ball bearing jockey wheels, and these will have to be overhauled like hub bearings. Careful not to loose the bb's! It is helpful to work over a clean white rag.

AFA rust - Oxalic acid in the form of Barkeeper's Friend is available in most grocery stores. Oxalic acid is also sold as one of several types of wood bleach for clearing rust stains from wood. I don't really like the aluminum foil and vinegar method for rust removal. I prefer soaking with oxalic acid for a time, and then polishing with simichrome. Naval jelly works too. Evaporust is well regarded and possibly the best option. I have no experience with it.